Ahh, sorry. Yes, there are limitations around edge purging (how many you can do at a time, and how long it takes for the purges to occur). All of these are also dependent on parameters defined by Akamai. I'll pass the feedback on to our product team as we try to make that experience better. Thanks!
Actually I'm talking about what you refer to as edge purge (http://www.rackspace.com/blog/cloud-files-cdn-gets-edge-purg...) and AWS refers to as invalidations.